The quarry was first developed in 1770 by Richard Pennant, later Baron Penrhyn although it is likely that small-scale slate extraction on the site began considerably earlier. Slates from the quarry were transported to the sea at Port Penrhyn on the narrow gauge Penrhyn Quarry Railway built in 1798, one of the earliest railway lines. In the 19th century the Penrhyn Quarry, along with the Dinorwic Quarry, dominated the Welsh slate industry.
The quarry holds a significant place in the history of the British Labour Movement as the site of two prolonged strikes by workers demanding better pay and safer conditions. The first strike lasted eleven months in 1896. The second began on 22nd. November 1900 and lasted for three years.
The quarry still produces slate though at a much reduced capacity from its heyday at the end of the 1800s. From 1964 until 2007 it was owned and operated by Alfred McAlpine PLC. In 2007 it was acquired by Rigcycle Limited.